Mega Code Archive
Move the curve control point and redraw the curve
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import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.MouseEvent;
import java.awt.geom.CubicCurve2D;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
import java.awt.geom.QuadCurve2D;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.event.MouseInputAdapter;
public class MainClass {
public static void main(String[] args){
JFrame frame = new JFrame();
frame.getContentPane().add(new CurveApplet());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(200, 200);
frame.setVisible(true);
}
}
class CurveApplet extends JPanel {
public CurveApplet() {
super(new BorderLayout());
pane = new CurvePane();
add(pane,"Center");
MouseHandler handler = new MouseHandler();
pane.addMouseListener(handler);
pane.addMouseMotionListener(handler);
}
class CurvePane extends JComponent {
public CurvePane() {
quadCurve = new QuadCurve2D.Double(
startQ.x, startQ.y,
control.x, control.y,
endQ.x, endQ.y);
cubicCurve = new CubicCurve2D.Double(
startC.x, startC.y,
controlStart.x, controlStart.y,
controlEnd.x, controlEnd.y,
endC.x, endC.y);
}
public void paint(Graphics g) {
Graphics2D g2D = (Graphics2D) g;
quadCurve.ctrlx = ctrlQuad.getCenter().x;
quadCurve.ctrly = ctrlQuad.getCenter().y;
cubicCurve.ctrlx1 = ctrlCubic1.getCenter().x;
cubicCurve.ctrly1 = ctrlCubic1.getCenter().y;
cubicCurve.ctrlx2 = ctrlCubic2.getCenter().x;
cubicCurve.ctrly2 = ctrlCubic2.getCenter().y;
g2D.setPaint(Color.BLUE);
g2D.draw(quadCurve);
g2D.draw(cubicCurve);
g2D.setPaint(Color.RED);
ctrlQuad.draw(g2D);
ctrlCubic1.draw(g2D);
ctrlCubic2.draw(g2D);
Line2D.Double tangent = new Line2D.Double(startQ, ctrlQuad.getCenter());
g2D.draw(tangent);
tangent = new Line2D.Double(endQ, ctrlQuad.getCenter());
g2D.draw(tangent);
tangent = new Line2D.Double(startC, ctrlCubic1.getCenter());
g2D.draw(tangent);
tangent = new Line2D.Double(endC, ctrlCubic2.getCenter());
g2D.draw(tangent);
}
}
Point2D.Double startQ = new Point2D.Double(50, 75);
Point2D.Double endQ = new Point2D.Double(150, 75);
Point2D.Double control = new Point2D.Double(80, 25);
Point2D.Double startC = new Point2D.Double(50, 150);
Point2D.Double endC = new Point2D.Double(150, 150);
Point2D.Double controlStart = new Point2D.Double(80, 100);
Point2D.Double controlEnd = new Point2D.Double(160, 100);
Marker ctrlQuad = new Marker(control);
Marker ctrlCubic1 = new Marker(controlStart);
Marker ctrlCubic2 = new Marker(controlEnd);
QuadCurve2D.Double quadCurve;
CubicCurve2D.Double cubicCurve;
CurvePane pane = new CurvePane();
class Marker {
public Marker(Point2D.Double control) {
center = control;
circle = new Ellipse2D.Double(control.x - radius, control.y - radius, 2.0 * radius,
2.0 * radius);
}
public void draw(Graphics2D g2D) {
g2D.draw(circle);
}
Point2D.Double getCenter() {
return center;
}
public boolean contains(double x, double y) {
return circle.contains(x, y);
}
public void setLocation(double x, double y) {
center.x = x;
center.y = y;
circle.x = x - radius;
circle.y = y - radius;
}
Ellipse2D.Double circle;
Point2D.Double center;
static final double radius = 3;
}
class MouseHandler extends MouseInputAdapter {
public void mousePressed(MouseEvent e) {
if (ctrlQuad.contains(e.getX(), e.getY()))
selected = ctrlQuad;
else if (ctrlCubic1.contains(e.getX(), e.getY()))
selected = ctrlCubic1;
else if (ctrlCubic2.contains(e.getX(), e.getY()))
selected = ctrlCubic2;
}
public void mouseReleased(MouseEvent e) {
selected = null;
}
public void mouseDragged(MouseEvent e) {
if (selected != null) {
selected.setLocation(e.getX(), e.getY());
pane.repaint();
}
}
Marker selected = null;
}
}
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